Thanks;
the front of the reservoirs sit back behind the notch int eh curved section and clamp around the very front and rear of the tube. The rubber cushion I'm using is 1/4 inch thick old style mini golf putting tee pad material. when the muzzle's bolted in top and bottom, it's stout. If I hit something hard enough to crumple it, the mounts should push up and back and the rubber should protect them in case some of the metal bends and angles upwards -- they'll be the least of my worries if i hit something that hard.
Got another chunk of time to work on it tonight--storms shut my place down early.